A Tunisian family flees tear gas during a demonstration by fundamentalists in Tunis.

Photo: Associated Press

A Tunisian family flees tear gas during a demonstration by...

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Tunisian opposition leader Chokri Belaid was shot to death outside his home.

Photo: Hassene Dridi, Associated Press

Tunisian opposition leader Chokri Belaid was shot to death outside...

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A relative of slain opposition leader Chokri Belaid cries at his coffin at the parents' home near Tunis, Thursday, Feb.7, 2013. The Islamist party dominating Tunisia's ruling coalition on Thursday rejected its own prime minister's decision to form a non-partisan technocratic government to try to appease critics, signaling that the political crisis brought on by the assassination of a prominent leftist politician is far from over. (AP Photo/Amine Landoulsi)

A Tunisian student wept in my international law class Wednesday morning when describing the assassination of left-wing opposition leader Chokri Belaid that day in her country's capital. It was eerily familiar.

Twenty years ago when I was a law student in the United States, I was visiting my father in neighboring Algeria when assassinations by fundamentalist armed groups began. On June 22, 1993, I came home to find my father furious over the murder that day of his one-time colleague, sociologist Mohamed Boukhobza, who like Belaid was an outspoken opponent of fundamentalism. In his last interview, Boukhobza insisted, "The choice is simple: modernity or death." That remains true across North Africa today.

The situation has been deteriorating of late in Tunisia, the birthplace of the Arab Spring. "The jihadist menace looms over the country," Algerian newspaper El Watan warned the morning of Belaid's killing. Belaid, who had been repeatedly threatened, claimed that fundamentalists were compiling death lists. His family accuses the ruling Ennahda Party leader Rached Ghannouchi of responsibility for his murder, which Ghannouchi denies.

But the Ennahda Party clearly has acquiesced to rising violence by the Salafi, the most rigid fundamentalists, and pushes a theocratic agenda despite its undeserved international reputation as moderate. Human rights lawyer Alya Chammari could see this coming when I interviewed her in Tunis in October 2011. She defended Ennahda political prisoners incarcerated during President Zine el-Abidine Ben Ali's brutal regime - the first to fall in the Arab Spring revolutions. By fall 2011, when the Ennahda Party won constituent assembly elections, she was asking her former clients if they would defend her.

When the killing started in Algeria in 1993, there was little international outcry. Fundamentalist violence ultimately claimed between 100,000 and 200,000 lives over 10 years. My father - a professor at the University of Algiers who dared teach evolution - found a note on his kitchen table saying "consider yourself dead," and had to flee his apartment. He kept speaking out, but was saddened by the lack of international support people like him received.

That is why I know how important it is to react urgently to Wednesday's shooting of a brave Tunisian secularist by standing with those who continue his work. A 48-year-old lawyer and father of two, Belaid is being buried Friday.

Tunisian civil society activists are resilient. As Belaid himself said, "They can kill me, but they cannot silence me." His widow found the courage to march in Tunis, flashing the victory sign, the day he died. Since then, outraged demonstrators have braved abuse by Salafi mobs and police, chanting, "The people want a new revolution," and denouncing "Ennahda, torturers of the people."

The U.S. government must stop supporting so-called moderate Islamists like Ennahda, who are anything but and who open the floodgates for their even more extreme brethren. Such an approach has been questioned since the Salafi attack on the U.S. Embassy in Tunis last fall, but now it must be renounced completely. Liberal opinion in the United States should champion those who wage North Africa's struggle against fundamentalism, whether in Egypt or Tunisia. Their defense of secularism and equality should be our fight, too.

My hope is that, unlike the early killings in Algeria, Chokri Belaid's assassination will be the last in Tunisia. But Tunisians cannot realize that hope alone.

Karima Bennoune is a law professor at the UC Davis School of Law and author of the forthcoming book, "Your Fatwa Does Not Apply Here: Untold Stories From the Fight Against Muslim Fundamentalism."